William f



(No Model.)

W. P. CUNNINGHAM.

VALVE POE. STEAM BOILERS.

No. 433,618. Patented Aug. 5, 1890.

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' UNITED STATES PATENT" OFFICE.

WILLIAM F. CUNNINGHAM, OF BROOKLYN, NEl/V YORK, ASSIGNOR OF ONF- HALETOENOOH RUTZLER, OF SAME PLACE.

VALVE FOR STEAM-BOILERS.

SPECIFICATION forming part of Letters Patent No. 433,618, dated August5, 1890. Application filed November 2, 1839. Serial No. 329,027. (Nomodel.)

To aZZ whom, it may concern.-

Be it known that I, ILLIAM F. CUNNING- HAM, of the city of Brooklyn, inthe county of Kings and State of New York, have invented a new anduseful Improvement in Valves for Steam-Boilers, Radiators, and otherPurposes, of which the following is a specification, reference being hadto the accompanying drawings.

m This invention relates to combined pressure and vacuum valves,consisting of a safety valve to prevent explosion by pressure within anapparatus and a vacuum-valve to prevent collapsion by pressure Withouton the r 5 formation of a vacuum within the apparatus.

My invention consists in the novel combination, hereinafter describedand claimed, of the two valves and their box, whereby great simplicityis obtained.

Figure 1 is a central vertical sectional view of the combined safety andvacuum valve embodying my invention. Fig. 2 represents a horizontalsection in the line a m of Fig. 1. Fig. 3 represents a horizontalsection in the line 3 3 of Fig. 1.

Similar letters of reference designate corresponding parts in all thefigures.

A is the valve-box, having in its bottom an opening a, through whichcommunication is to be made with the boiler, radiator, or other apparatus, to which the combined safety and vacuum valve is to be applied.The connection of this box with the boiler may be made by a screw-threadZ) around the said opening a or in any other convenient manner. At thetop of the opening a is a safety-valve seat 0, to which anoutwardly-opening safety-valve 13 is fitted. The stem B of this valvepasses through a guide A in the top of the valve- 0 box A and a guide Awithin the said box, and is represented as being loaded by a ball orweight D, directly applied to its upper end, but may be loadedexternally in any wellknown way. The said guide A is formed by 4 5simply making the said box with a contracted neck and boring out thesaid neck for the stem to pass through. Openings d are provided in thesides of the box A for the escape of steam when the safety-valve B islifted by excessive pressure at the opening a.

I will now proceed to describe my improvement. The valve-stem B is madehollow, and

an opening is made through the valve B in line with the stem, so thatthere is a passage directly through the said valve and stem,and 5 aroundthe lower end of this passage is formed a seat 6 for the vacuum-valve E,the said seat facing in the opposite direction to the safetyvalve seat 0and the two valves also facing in opposite directions. The vacuum-valveE is closed upward against the seat 6 by pressure through the opening a.In the sides of the hollow safety-valve stem E there are openings (2, sothat air entering the valve-box A through the opening (Z may passthrough the said openings 6 through the passage formed in the stem B andvalve B and through the valve-seat 6 when the valve B is opened, as

it will be when the pressure at the opening a is considerably less thanthe pressure of the atmosphere.

The stem E of the vacuum-valve B passes into the passage provided in thesafety-valve and its hollow stem B, and in order that the said stem Emay not interfere with the free ingress of air through the said passagethe said stem must be so constructed that While it is guidedwithin saidpassage there may be room for the circulation of air outside of itwithin the said passage, and for this pur- 8o pose I have represented itof polygonal form in its transverse section, (see Figs. 2 and 3,) thesaid passage having a circular transverse section.

In order that the vacuunrvalve may always remain closed until thepressure in the opening a is somewhat lower than that of the atmosphere, a light spring f is applied to it for the purpose of closingit. The strength of this spring, which is represented as coiled 0 aroundthe stem, needs only to be slightly in excess of what is necessary tosustain the weight of the valve E. This spring is supported upon aninternal shoulder g, provided in the interior of the safety-valve stemB, and its upper end presses against a head or collar 71 secured on thetop of the valve-stem E. In order that the air may pass by the shoulderg in the safety-valve stein the opening provided in the said shoulderfor the stem Ioe E is made circular and the portion of the said a stemwhich passes through it is made poly;

onal.

In order to enable the valve-stern E to be guided in the lower part ofthe passage in the safety-valve and its stem and yet to pass theshoulder g, provided for the spring, the upper part of the said stein Eis made smaller than the lower part.

According to my invention, a vacuum-val ve is provided in the same boxwith a safetyvalve without any unnecessary enlargement of thesafety-valve box or of the safety-valve,

and Without any stuiling-box, and neither valve interferes in any waywith the operation of the other; the safety-valve being permitted toopen in the usual Way by excessive pressure within the apparatus towhich it is applied and the vacuum-valve being free to open when thepressure within the apparatus is sensibly less than that of theatmosphere.

What I claim as my invention, and desire to secure by Letters Patent, is

The combination, with the pressure-valve B, having a hollow slotted stem13' and a vacuum-valve E, arranged Within said pressure-valve, of theValve-box A, having lateral openings d, an inner guide A for said stemB, and an outer guide consisting of the contracted neckA through whichthe said stem projects to be loaded externally, substantially as hereinset forth.

WVILLIAM F. CUNNINGHAM.

Witnesses:

FREDK. HAYNES, GEO. BARRY.

